Technical Field
The present invention relates to a driver circuit and method, particularly to an LED driver circuit and method.
Description of Related Art
Light emitting diodes (LEDs) are replacing conventional lighting technologies for their advantages including less power consumption, smaller sizes and low levels of pollution. Current LEDs are mainly driven with the dimming technique using pulse width modulation (PWM), and are thus caused to switch rapidly between zero-current state and full-current state at a rate dependent on the pulse wave frequency, which results in the flashing of LEDs. The LED flashes, though imperceptible to the human eye due to persistence of vision, tend to cause eye fatigue after prolonged hours of exposure to these lights. It matters in particular when it comes to LED-based surgical lighting systems. In the field of surgery where surgeons are often subject to long surgical procedures and the health of patients is at stake, the eyes of both parties may be seriously fatigued by flashes that these lighting systems produce. On the other hand, these LED-based lighting systems are likely to produce flashes or stripes on the monitor used by medical institutes or surgeons for observing surgical procedures from time to time. In view of the above, the disadvantageous flashes resulted from the technique of driving current LEDs have become an urgent problem waiting to be addressed.